1. Field of the Invention
The present invention relates to a data processing device, and a control method which is applied to the data processing device.
2. Related Background Art
Conventionally, a data processing device which operates in either a power saving state or an operating state has been known. Here, in the power saving state, the data processing device can operate with the power consumption low, by shutting off the power supply to each constitutional element in the data processing device.
Incidentally, in the case where the data processing device operates in the power saving state, the power consumption of the device can surely be lowered. However, in that case, in order to cause the data processing device which is in the power saving state to again execute the data process, the image process and the like, it is necessary to shift the state of the data processing device from the power saving state to the operating state. In this connection, to shift the state of the data processing device from the power saving state to the operating state, a predetermined shift time is of course necessary. For this reason, the time necessary to start the data process, the image process and the like is prolonged by the relevant shift time.
To solve such a problem, the technique for achieving the high-speed operation of the data processing device by lowering as much as possible the shift time for shifting the state of the device from the power saving state to the operating state (for example, Japanese Patent Application Laid-Open No. 2000-196789; hereinafter called the document 1).
The data processing device (facsimile machine) in the document 1 executes the shift operation including the cleaning of the photosensitive member in a case where the toner cartridge is exchanged in the power saving state, and executes the shift operation not including the cleaning of the photosensitive member in a case where the toner cartridge is not exchanged in the power saving state. Thus, in the case where the toner cartridge is not exchanged in the power saving state, the data processing device (facsimile machine) in the document 1 can shift from the power saving state to the operating state at higher speed as compared with the case where the toner cartridge is exchanged in the power saving state.
Incidentally, the data processing device (facsimile machine) in the document 1 comprises the plural reception units (that is, the modem 7, the NCU (network control unit), the PC I/F (personal computer interface) 6) for receiving the data transmitted from an external device. Thus, when a data reception request is input to any one of the plural reception units in the power saving state of the data processing device, the data processing device starts to shift from the power saving state to the operating state.
The document 1 discloses that the data processing device is set to come into the power saving state by controlling or suppressing the power to be supplied to, e.g., the heater or the like. That is, it is possible to achieve the power saving by controlling or suppressing the power to be supplied to the heater or the like. However, in order to further lower the power consumption, it is also necessary to set the CPU of controlling the data processing device and the plural reception units of receiving the data from the external device to be in the power saving state. In such a case, although the power consumption can surely be controlled or suppressed, in the meantime, the shift time for shifting the CPU and the reception units from the power saving state to the operating state is necessary to cause the data processing device to come into the operating state as a whole.
Under the circumstances, if the order of returning the states of the plural reception units from the power saving state (that is, the state incapable of receiving data including image data) to the operating state (that is, the state capable of receiving data including image data) is previously determined, the problem that the shift time for shifting the state from the power saving state to the operating state is prolonged occurs. For example, when the data reception request is input to the modem (that is, the unit of receiving facsimile data through a public network), if the returning process of the NCU (that is, the unit of receiving data including image data through a network) for returning the state of the NCU from the power saving state to the operating state is preferentially executed according to the previously determined order, the returning process of the modem cannot be executed until the returning process of the NCU ends in spite of the fact that any data reception request is not input to the NCU. As a result, the time necessary to process the reception data by the modem to which the reception request has been input is involuntarily prolonged.